Antenna structures

ABSTRACT

There is disclosed an antenna structure utilizing a loop having an annular ring coupled thereto and lying in a substantially horizontal plane transverse to the plane of the loop. The ring has reflector and director elements mounted thereon, and on opposite sides of the ring to offer increased directivity to the structure. A pair of dipoles are also utilized in the antenna structure. The dipoles are mounted on a first rotatable base assembly and the loop is mounted on a second rotatable base assembly. These base assemblies are rotatable with respect to a fixed base member and are controlled in rotation by means of a knob to permit azimuth orientation of the antennas.

United States Patent m1 Callaghan ANTENNA STRUCTURES [75] Inventor: JohnDavid Callaghan, Cherry Hill,

[73] Assignee: RCA Corporation, New York, N.Y.

[22] Filed: Aug. 16, 1971 [21] Appl. No; 171,868

[52] US. Cl. 343/726, 343/758, 343/741,

[51] Int. Cl. H0lq 3/02 [58] Field of Search 343/805, 809, 741,

[56] References Cited UNITED STATES PATENTS 2,657,312 10/1953 Saranga343/727 3,478,361 11/1969 Middlemark 343/805 11/1970 Perkins 343/726June 12, 1973 Primary Examiner-John S. Heyman Attorney-Eugene M.Whitacre [5 7] ABSTRACT There is disclosed an antenna structureutilizing a loop having an annular ring coupled thereto and lying in asubstantially horizontal plane transverse to the plane of the loop. Thering has reflector and director elements mounted thereon, and onopposite sides of the ring to offer increased directivity to thestructure. A pair of dipoles are also utilized in the antenna structure.The dipoles are mounted on a first rotatable base assembly and the loopis mounted-on a second rotatable base assembly. These base assembliesare rotatable with respect to a fixed base member and are controlled inrotation by means of a knob to pennit azimuth orientation of theantennas.

8 Claims 9 Drawing Figures Patented June ,12, 1973 2 Sheets-Sheet 1INVENTOR. John D. Callaghan ATTORN Patehtd June 12, 1973' 2 Sheets-Sheet2 INVENTOR. John D. Callaghan TORNEY ANTENNA STRUCTURES atively compactin order to assure that the assembly is not too large so as to interferewith the aesthetic preferences of the consumer.

Due to the fact that indoor antennas have to be capable of receiving theentire VHF and/or UHF bands, such antennas have conventionally beenadjustable. For example, typical VHF antennas utilize a dipole sys-, temwhereby the consumer can increase the length and adjust the angle of thedipoles which are fabricated in a telescopic structure, to receive thevarious channels and to achieve optimum signal strength.

It is known that when the consumer is adjusting the dipoles, his bodycapacitance and the consequent loading presented by his body, when he isaccessing these elements, serves to change the effective response of theantenna.

It is therefore an object of this invention to provide an improved VHFand UHF indoor antenna system'.

Another object is to provide an improved VHF-UHF antenna, the elementsof which can be varied or rotated without making physical contact withthe same.

According to an embodiment of the present invention, a UHF antennastructure comprises a loop of a given configuration, an annular ring iscoupled to said loop and lies in a plane transverse to the planecontaining the loop, the annular ring has mounted thereon at least onebeam shaping element to afford increased directivity for the structure.

A UHF-VHF structure employs the loop and ring structure together with apair of extendible dipoles. The dipoles and the loop are rotated inopposite directions by means of a pulley or gear arrangement undercontrol of a single knob. The consumer can therefore achieve antennaazimuth adjustment without manually accessing the antenna structure.

Other objects, features and advantages of this invention will becomefully apparent from the following detailed description taken inconjunction with the accompanying figures, in which:

FIG. 1 is a front view of a UHF-VHF indoor antenna according to thisinvention;

FIG. 2 is a top view of the antenna shown in FIG. 1;

FIG. 3 is a top view of an alternate embodiment of an antenna;

FIG. 4 is a partial front view of another embodiment of a UHF antennaaccording to this invention;

FIG. 5 is a top view of a rotatable support assembly for an antennaaccording to this invention;

FIG. 6 is a side cross-sectional view' of the pulley mechanism necessaryto provide rotation of such antennas;

FIG. 7 is a schematic diagram of a threading arrangement and a pulleyassembly useful in explaining and accomplishing the rotation operationaccording to this invention;

FIG. 8 is a perspective view of an antenna employing two tilted annularrings;

FIG. 9 is a side view of the antenna of FIG. 8. Referring to FIG. 1,there is shown a UHF-VHF antenna according to this invention. The VHFportion of the antenna comprises two dipoles 10 which are adjustable inlength by means of a telescopic arrangement as is well known in the art.The UHF portion of the antenna includes a loop 11 which has locatedabout its equatorial plane a director/reflector ring 12.

The UHF loop 11 is mounted on a rotatable base assembly 14, while theVHF dipoles 10 are mounted on a rotatable base assembly 15. The baseassemblies 14 and 15 rotate with respect to a fixed base member 17 andare controlled in rotation by means of a knob 18.

Briefly, the director/reflector ring 12 rotates with the UHF loop 11 inany direction for a full 360. This flexibility assures a relativelyefflcient reception of all color and black and white UHF signals. TheVHF dipoles 10 are chrome plated, five-section telescopic dipole deviceswhich rotate to assure efficient pick-up of VHF signals. For example,due to the telescopic nature of the VHF dipoles, they can be extended toa typical length of about 46 inches. The dipoles l0 rotate in theopposite direction to that of the UHF antenna assembly. The consumer cancounterrotate the VHF and UHF structures to obtain antenna patternorientation suitable for the particular environment.

The antenna is also capable of receiving FM signals as well, whichsignals are in the center of the VHF TV band. The FM and VHF receptionis further enhanced by two axial inductors 16 associated with each ofthe VHF dipole elements 10.

As indicated, there is no need to rotate the VHF and UHF elements byhand. These elements are counterro tatable simultaneously by the singlerotator knob 18. The exact nature of the drive assembly and coupling ofthe knob 18 will be described. subsequently.

Referring to FIG. 2, there is shown a top view of the UHF assembly. TheUHF loop 11 is surrounded at its equatorial central plane by adirector/reflector element 12. The element 12 is'an annular disc,fabricated from a suitable plastic material and has deposited thereon areflector assembly 20 and a director assembly 21. The reflector 20 andthe director 21 assemblies are typically fabricated from a suitableconducting material such as aluminum or copper. I

The reflector assembly-20comprises a square wave typeof pattern whichserves to give an increase in the effective length of the reflector,thus permitting one to obtain a greater effective length in a smallerarea. This permits one to obtain greater antenna directivity for the UHFband in a relatively small area. It is noted that the reflector assembly20 could be sinusoidal or some other suitable configuration. Thedirector assembly 21 is a curved metallic strip of an arcuateconfiguration. A plurality of apertures or windows 22 are located on thesurface of director 21 and serve to enhance the aesthetic properties ofthe entire assembly. It is apparent that the electrical characteristicsof the director will be provided by a single continuous arcuatestructure having no apertures.

As indicated, the ring 12 is located approximately at the equatorialaxis or central axis of the loop 11. The UHF antenna 11 and associatedassembly is a relatively unidirectional type antenna because of thereflector 20 and the-director 21 which are coupled to the UHF loop.

In the normal mode of coupling a director and a reflector to a UHF loopor to an antenna, a relatively short element would be placed in front ofthe loop to serve as the director assembly. On the other hand, arelatively long element would be placed behind the loop to serve as thereflector assembly. This configuration provides a relatively bulkystructure which would occupy or define a relatively wide antenna areapattern when rotated.

In the configuration shown the reflector 20 is curved. Furthermore, thereflector is also of a zigzag type of configuration so that it isrelatively long and yet consumes a relatively small amount of space. Dueto the fact that the reflector and the director are mounted to the UHFloop element 11 in the equatorial plane of the loop, this affords afairly substantial savings in space consumed by the antenna which iscritical to indoor antenna structures. As will further be explained, allthree elements, namely, the loop 11, the reflector 20 and the director21 are rotated simultaneously.

The UHF antenna configuration shown utilizes a conventional circularloop 11 which is approximately 7 inches in diameter. It is known thatrotation of such a circular loop sweeps out a spherical volume. In orderto minimize size, it would be desirable to incorporate unidirectivityinside the swept sphere. As indicated above, a parasitic director wouldafford to do this and would actually present no problem, since for theUHF band it will be short enough to lie along the equator of the sweptsphere. However, a reflector which would be tuned for the low end of aUHF band would be too long to lie along the equator. Hence, in themanner described above, a reflector 20 may be shortened effectively bygiving it a zigzag or sinuous form, and it is further curved around thesurface of the annular ring which affords a further reduction in thearea occupied, thus providing a structure capable of providing a lowswept volume. The low swept volume concept is particularly useful whenthe antenna is used in the same assembly with the VHF dipoles 10, sincethis particular configuration tends to minimize the required dipolespacing.

Referring to FIG. 3, there is again shown the circular UHF loop antenna11 with the director/reflector ring 12. However, in FIG. 3, a sinusoidalconfiguration refle'ctor element curved about the surface of the ring 12is used which again serves to reduce the effective length of thereflector assembly, while affording increased directivity for the UHFantenna assembly.

FIG. 4 shows a UHF loop antenna 30 with a director/reflector ring asshown in FIGS. 2 and 3 mounted on an inclined axis with respect to theequatorial axis. This particular configuration will operate to affordincreased selectivity as the configuration shown in FIG. 1 with certainaesthetic advantages. Alternatively, two rings may be utilized. One ringwould be tilted up and one ring would be tilted down with respect to theequatorial plane. Each of these rings would carry both a reflectorelement and a director element. This combination would afford to offersome stacking gain for the entire antenna assembly. This configurationwill be explained subsequently with reference to FIGS. 8 and 9.

Referring to FIG. 5, there is shown the mounting plates 14 and 15. Thecross-hatched areas 32 and 33 on the mounting plate 15 show the locationof the VHF dipoles such as of FIG. 1, while the darkened areas on themounting plate 14 show the location of the ends of the UHF loop. Thearrows on each of the rotatable plates 14 and indicate the direction ofrotation of these plates with respect to each other. It can therefore beseen that the plates 14 and 15 rotate counter to each other.

Referring to FIG. 6, there is shown a cross-sectional view of the plates14 and 15 and mechanical assemblies which may be coupled to a suitabledriving arrangemerit to afford such rotation. A partial UHF loop 11 isshown mounted to a plate 14. The plate 14 has a central aperture 35. Themounting portion of the plate 14 is also coupled to a bottom pulleyassembly portion 36, which has a wire or thread accommodating groove 38around the periphery thereof.

The VHF plate 15 is circular in nature and is relatively symmetricallylocated about the central aperture 35 of the UHF plate 14. The VHF plate15 is also contiguous with a bottom pulley assembly 39 having a threadaccommodating groove 40 located about the periphery thereof.

Both the assemblies 14 and 15 rotate with respect to a fixed top portion42 of the antenna assembly. The top portion 42 would be analogous to thetop surface of the base member 17 of the antenna shown in FIG. 1.

Referring to FIG. 7, there is shown the UHF pulley 36 and the VHF pulley39 which are offset one from the other in order to gain a clearexplanation of the mechanical operation. Member 18 references thecontrol knob 18 of FIG. 1, which actually is a control knob coupled to apulley assembly. Member 43 references a roller or idler used as part ofthe mechanical path to accommodate a loop of thread to aid in affordingrotation of the antenna assembly.

As indicated, member 36 represents the UHF drive pulley while member 39represents the VHF drive pulley. These have been shown with theircentral axes offset in order to clarify the mode of operation, but ascan be seen from FIG. 6, the two assemblies may actually be concentricto one another.

The threading assembly is as follows. A thread 50, which may be a wireor a cord, is directed as follows.

The exact direction and threading arrangement will be clearer ifreference is made to the associated arrows drawn at specified intervalsalong the assembly.

The thread 50 passes about the pulley associated with the control knob18 and thence to a groove in the idler 43. The thread 50 is directedabout the idler 43 and then on to the groove associated with the VHFdrive gear 39. The thread 50 wraps about the VHF drive gear 39 foralmost 360 and then comes off the VHF drive gear to encircle a fixed oranother idler member 51. The cord 50 is wrapped about member 51 forapproxirnately 180 and is then directed within the groove of the UHFdrive pulley 36, where it encircles the same for approximately l and isthence directed from the drive pulley 36 back into the groove of thecontrol knob 18 and hence to the starting point. p

It can be seen that if the control knob 18 is rotated in thecounterclockwise direction, the drive gear 39 will rotate in theclockwise direction while drive pulley 36, because of the translationvia member 51, will rotate in the counterclockwise direction. Therefore,the control knob and associated pulley 18 will cause the VHF turntableor gear drive pulley to rotate clockwise, while the UHF drive pulley 36will rotate counterclockwise or in the same direction as the knob 18.

Rotation of the antennas by the knob 18 has the advantage of keeping theusers hands away from the antenna and, as indicated, this substantiallyreduces body coupling effects. It can be seen that, since the VHFdipoles are bidirectional, the VHF antenna needs only l80 rotation. Onthe other hand, the UHF loop is not bidirectional and requires a 360loop rotation. The desired 360 loop rotation and the 180 VHF dipolerotation can easily be accomplished by rotating the UHF loop twice asfast as the VHF dipoles. This requires a half size pulley or drive gearfor the UHF loop 11 and the relationship is well known to those skilledin the art.

Referring to FIGS. 8 and 9, there is shown a UHF loop 60 with twoannular rings 61 and 62 mounted inclined with respect to each other andat an angle of approximately 45 with loop 60. Each annular ring has areflector and a director element mounted thereon with the reflector ofone element disposed above the reflector of the other; Similarly, thedirectors are also stacked in the vertical plane. The configurationserves to assure that the reflector/director assembly couples with themajor current carrying portions of the loop 60 which lie mainly on theupper and lower segments of the loop 60.

Increased performance in terms of directivity and gain can be achievedby this configuration because of the addition of the extrareflector/director structures.

What is claimed is:

1. An antenna structure, comprising:

a. a loop of a given configuration,

b. an annular ring coupled to said loop and lying in a substantiallyhorizontal plane transverse to the plane containing said loop, and

c. at least one beam shaping element mounted on said annular ring andextending along a portion of the surface thereof to provide increaseddirectivity for said antenna.

2. The antenna according to claim 1 wherein said beam shaping element isof a serpentine configuration fabricated from a conducting metal.

3. The antenna according to claim 1 wherein said beam shaping element isof an arcuate configuration fabricated from a conducting metal locatedon a surface thereof.

4. The antenna according to claim 1 wherein said loop is of a circularconfiguration.

5. The antenna according to claim 1 further comprising: t

.a. means coupled to said loop for rotating the same.

6. An antenna structure for responding to UHF and VHF signaltransmissions, comprising:

a. first and second rotatable base assembly members having a commoncentral axis about which either can be rotated,

b. a pair of extendible dipoles mounted on said first base assembly,said dipoles of a length sufficient to accommodate VHF signals,

c. a loop of a given configuration mounted on said second base assembly,said loop of a diameter sufficient to accommodate UHF signals, and i d.means coupled to said first and second base assemblies for rotating thesame to thereby provide for directivity pattern orientation. of each ofsaid VH and UHF antennas.

7. An antenna structure for responding to UHF and VHF signaltransmissions, comprising:

a. first and second rotatable base assembly members having a commoncentral axis about which either can be rotated,

b. a pair of extendible dipoles mounted on said first base assembly,said dipoles of a length sufficient to accommodate VHF signals,

c. a loop of a given configuration mounted on said second base assembly,said loop of a diameter sufficient to accommodate UHF signals,

d. an annular ring coupled to said loop and lying in a substantiallyhorizontal plane transverse to the plane containing said loop,

e. at least one beam shaping element mounted on said annular ring andextending along a portion of the surface thereof to provide increasedsensitivity for said antenna, and

f. means coupled to said first and second base assemblies for rotatingthe same to thereby provide for directivity pattern orientation of eachof said VHF and UHF antennas.

8. An antenna structure, comprising:

a. a loop of a given configuration,

b. an annular ring coupled to said loop and lying in a substantiallyhorizontal plane transverse to the plane containing said loop,

0. a reflector of a serpentine configuration mounted along a firstportion of said annular ring for providing increased directivity to saidantenna structure, and

d. a director of an arcuate configuration located thereon, mounted on asecond different portion of said annular ring to provide a furtherincrease of directivity for said antenna structure.

1. An antenna structure, comprising: a. a loop of a given configuration,b. an annular ring coupled to said loop and lying in a substantiallyhorizontal plane transverse to the plane containing said loop, and c. atleast one beam shaping element mounted on said annular ring andextending along a portion of the surface thereof to provide increaseddirectivity for said antenna.
 2. The antenna according to claim 1wherein said beam shaping element is of a serpentine configurationfabricated from a conducting metal.
 3. The antenna according to claim 1wherein said beam shaping element is of an arcuate configurationfabricated from a conducting metal located on a surface thereof.
 4. Theantenna according to claim 1 wherein said loop is of a circularconfiguration.
 5. The antenna according to claim 1 further comprising:a. means coupled to said loop for rotating the same.
 6. An antennastructure for responding to UHF and VHF signal transmissions,comprising: a. first and second rotatable base assembly members having acommon central axis about which either can be rotated, b. a pair ofextendible dipoles mounted on said first base assembly, said dipoles ofa length sufficient to accommodate VHF signals, c. a loop of a givenconfiguration mounted on said second base assembly, said loop of adiameter sufficient to accommodate UHF signals, and d. means coupled tosaid first and second base assemblies for rotating the same to therebyprovide for directivity pattern orientation of each of said VHF and UHFantennas.
 7. An antenna structure for responding to UHF and VHF signaltransmissions, comprising: a. first and second rotatable base assemblymembers having a common central axis about which either can be rotated,b. a pair of extendible dipoles mounted on said first base assembly,said dipoles of a length sufficient to accommodate VHF signals, c. aloop of a given configuration mounted on said second base assembly, saidloop of a diameter sufficient to accommodate UHF signals, d. an annularring coupled to said loop and lying in a substantially horizontal planetransverse to the plane containing said loop, e. at least one beamshaping element mounted on said annular ring and extending along aportion of the surface thereof to provide increased sensitivity for saidantenna, and f. means coupled to said first and second base assembliesfor rotating the same to thereby provide for directivity patternorientation of each of said VHF and UHF antennas.
 8. An antennastructure, comprising: a. a loop of a given configuration, b. an annularring coupled to said loop and lying in a substantially horizontal planetransverse to the plane containing said loop, c. a reflector of aserpentine configuration mounted along a first portion of said annularring for providing increased directivity to said antenna structure, andd. a director of an arcuate configuration located thereon, mounted on asecond different portion of said annular ring to provide a furtherincrease of directivity for said antenna structure.